Not Applicable.
Not Applicable.
This Invention relates generally to clothes dryers, and, In particular to a clothes dryer having a fire suppression system.
Typical clothes dryers circulate heated air through a tumbler or rotating basket in order to dry wet clothes. In some instances, hot spots may develop. For example, a zipper pull, snap, or button can become hot and form a hot spot. In some instances, this hot spot can start clothes to smolder within the dryer. If not detected, the fire can spread within the dryer. It is thus desirable to detect the possibility of a fire condition within the drier.
Briefly stated, a clothes dryer of the present invention comprises a chamber having an inlet and an outlet, a perforated basket rotatable in the chamber, a heater which delivers heated air through the chamber inlet to the chamber, and a blower which forces air to pass along an air path from the inlet, through the basket, and out the outlet The dryer also includes a controller which is used to operate the clothes dryer. The controller is provided with a fire detection and suppression system which will detect a fire condition within the chamber and upon detection of a fire condition, activate a fire suppression system. The fire detection and suppression system includes, in addition to the controller, at least one temperature detector located proximate the chamber and which is in communication with the controller, a source of fire suppressing substance (preferably water) which is delivered to the chamber over a pathway; and a valve in the pathway controlled by the controller. The temperature detector sends a signal to the controller when a set point at the location of the temperature detector has been reached and/or exceeded. Preferably, the fire detection and suppression system includes two temperature detectorsxe2x80x94one at the inlet to the chamber and one at the outlet to the chamber. The controller opens the valve when a fire condition is detected, and closes the valve after a time sufficient to introduce a predetermined volume of the fire suppressing substance has passed. The inlet and outlet temperature detectors are preferably normally opened bi-metal thermostats which close a circuit when the set point temperature is reached and/or exceeded. The dryer can include a flow detector, such as a pressure sensor or flow rate sensor, which will send information to the controller to enable the controller to determine how long the water valve needs to remain opened to deliver the predetermined amount of fire suppressing substance to the chamber. The dryer can also be provided with an alarm which is activated by the controller when the controller detects a fire condition (i.e., when the set point at either of the temperature detectors is reached and/or exceeded).
The fire detection and suppression system operates as follows: based on the signal from the temperature detector, the controller determines if a fire condition exists. The controller will determine that a fire condition exists when it receives a signal from the temperature detectors that the set point for the detectors has been reached and/or exceeded. The controller will then deactivate the heater, the blower, and the basket motor, if they are running, and open the valve to allow the fire suppression material to enter the chamber. Once a predetermined amount of the fire suppressing material has entered the chamber, the controller will close the valve. If the dryer is provided with a flow detector, the controller will, based on the output from the flow detector, determine the amount of time required to release the predetermined amount of the fire suppressing material into the chamber. The closing of the valve occurs when the time period has elapsed. If the dryer does not include a flow detector, the controller can determine the required time period based upon the pressure in the flow path of the fire suppressing material. While fire suppressing material is being delivered to the camber, the controller will periodically activate the basket motor to jog the basket